4042400021 has 4 divisors (see below), whose sum is σ = 4409890944. Its totient is φ = 3674909100.

The previous prime is 4042400003. The next prime is 4042400027. The reversal of 4042400021 is 1200042404.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 4042400021 - 2¹⁴ = 4042383637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4042400027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183745445 + ... + 183745466.

It is an arithmetic number, because the mean of its divisors is an integer number (1102472736).

Almost surely, 2^4042400021 is an apocalyptic number.

It is an amenable number.

4042400021 is a deficient number, since it is larger than the sum of its proper divisors (367490923).

4042400021 is a wasteful number, since it uses less digits than its factorization.

4042400021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367490922.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 4042400021 is about 63579.8711936412. The cubic root of 4042400021 is about 1592.9901698433.

Adding to 4042400021 its reverse (1200042404), we get a palindrome (5242442425).

The spelling of 4042400021 in words is "four billion, forty-two million, four hundred thousand, twenty-one".